1. Field
The present disclosure generally relates to methods and system for cleaning the air that enters into or is used during the ice making process. In particular, the present disclosure uses of the following techniques to clean air: (1) inlet air filtration, (2) recirculation air filtration, (3) water filtration and disinfection, (4) use of an air curtain in the ice bin opening, and (5) provision of clean air to the air assist pump during the harvest cycle.
2. Discussion of the Background Art
The cleanliness of ice machines has been a challenge to ice machine manufacturers for years. The primary method is periodic sanitizing of food contact surfaces in the machine with a sanitizing agent. This is also sometimes augmented with the treatment of surfaces and components with known anti-microbials, such as a silver ion coating of surfaces. While this method is effective in controlling organism growth on the ice bin surfaces, it does not address the ingress of organisms into the ice making compartment.
One conventional means for sterilizing and cleaning ice making machines is shown in FIGS. 1A and 1B which illustrate two separate embodiments for external location of an add-on self-cleaning system 59. The automatic self-cleaning system 59 may also be built internal to the ice machine 30.
The Coolant/Refrigerant System
An embodiment of the automatic ice making system's coolant/refrigerant system is illustrated in FIG. 2.
In FIG. 2, the coolant/refrigerant system comprises a condenser 11, an evaporator 12 and a compressor 14. FIG. 2 illustrates a refrigerant supply line 20, a drier for the refrigerant 21, and an expansion device 13. The expansion device serves to lower the pressure of the liquid refrigerant.
When the compressor 14 is operating, high temperature, high pressure vaporous refrigerant is forced along a discharge line 26 back to the condenser 11. When the ice making system goes into its harvest cycle, a normally closed hot gas solenoid valve 40 opens and hot vaporous refrigerant is fed through line 15 into the evaporator 12.
Further details of the operation of this system can be gleaned from careful review of U.S. Pat. No. 4,878,361 and U.S. Pat. No. 4,907,422, which are incorporated herein in there entireties by reference thereto.
This coolant/refrigerant system in contact with the evaporator 12 also preferably contains a control circuit which causes the refrigeration system to cool down the ice mold to well below freezing at the start of the ice making cycle. This improvement is described in U.S. Pat. No. 4,550,572, which is incorporated herein in its entirety by reference thereto.
As a result, the ice-forming mold or evaporator plate in contact with the evaporator 12 is cooled well below freezing prior to the water pump in the water/ice system being energized to deliver water to the ice-forming mold.
The Water/Ice System
The water/ice system normally comprises a water supply or water source, a water reservoir or sump, drain valves from the sump to a line draining to the drain or sewer, water circulation mechanism, water distribution means, and appropriate connecting lines. Water is distributed across an ice-forming mold, or evaporator plate, and forms ice thereon. Unfrozen water flows down the plate onto a water curtain and is returned to the water sump. When ice has been formed as required, it is harvested and falls into the ice bin.
FIGS. 3A and 3B illustrate schematically the water/ice system, but does not show the ice collector bin or reservoir. In FIGS. 3A and 3B, a water supply 1 provides source water, normally tap water or tap water which has optionally been treated by filtration, ion exchange or the like to improve its quality. Attached lines control and direct the flow of water from the water supply to flow into the water sump 3. The sump is equipped with a level controller 2, a solenoid dump valve 9, a drain line 10, and is connected and supplies a water supply to the suction side of the circulating pump 4. Pump 4 circulates water from sump 3 to the distributor 7, where the water is directed over the evaporator plate 6 (also called the ice-forming mold or ice tray).
The water from the distributor 7 is directed across the evaporator plate 6 and, if not frozen to form ice on a first pass, is collected by the water curtain 5. This collected water is allowed to flow down the water curtain into the water sump or water reservoir 3, where it is collected and again circulated by the circulating pump 4 to the distributor 7 and recycled across the ice tray during the freezing cycle.
Once the ice forming on the evaporator plate 6 has reached a certain thickness, the water flowing over the surface of that frozen ice product reaches contact with the ice thickness probe 8, which signals the controller to stop the freeze cycle. The ice thickness probe can be varied in its distance from the planar surface of the evaporator plate so as to provide ice having a bridge thickness of from about 1/16 inch to about ¼ inch, preferably about ⅛ inch. This begins the harvest cycle.
In the harvest cycle, the coolant no longer is pumped through the evaporator. Instead, the hot gas solenoid valve 40 is opened and operated according to FIG. 2 and the teachings of the patents cited and incorporated above to route hot vaporous refrigerant from the compressor 14 to the evaporator 12 through a discharge line 26 and bypass line 15, thereby heating up the evaporator plate. This causes the ice to release from the evaporator plate and fall against the water curtain and into the ice collection reservoir.
As can be seen, when the ice falls away from the evaporator plate structure, it must fall against the water curtain which is hinged. The water curtain is pushed away from the evaporator plate, thereby opening an electrical contact on the water curtain and allowing the ice to fall into the ice bin. The water sump, evaporator plate and water curtain are placed in such a way that the ice must fall against the water curtain and into the bin and cannot fall into the water sump or water reservoir. Similarly, water flowing down the curtain is directed away from the ice bin and into the water sump when the curtain is not displaced by the harvested ice.
After the ice falls into the bin, the water curtain springs or swings back into its original position, again making contact with the electrode placed thereon and sending a signal indicating that the harvest cycle is complete and that a new freeze cycle may begin.
On re-initiation of the freeze cycle, refrigerant/coolant is again pumped from the compressor through the refrigerant/coolant system to the evaporator to pre-cool the evaporator for the period of time mentioned above, the hot gas solenoid valve is shut, and the water system begins its next cycle.
Periodically the solenoid drain valve 9 may be activated to drain the water in the water sump, which water has a tendency to build up concentration of water hardness chemicals, such as calcium salts and magnesium salts. Pure water freezes at higher temperatures than does water containing these, or other, dissolved salts. Also, water that contains higher levels of salts freezes at lower temperature and forms what the art terms “white ice.” Fresh water can be then recharged to the water/ice system, which inhibits the formation of white ice. When the solenoid valve is activated to the open position, the water sump is drained, the solenoid is then closed (normally after a preset time has passed), and the fresh water recharges the system. Normally this fresh water recharging and recycled water discharge occur when the ice thickness probe indicates ice build up and the harvest cycle is initiated. This stops the coolant circulation and the water circulation.
In spite of the precautions mentioned above, the circulating water can lead to the build up of certain deposits on metal surfaces in the water/ice system. Particularly prone to build up of these deposits are the surfaces of the water sump, the internal surfaces of connecting lines from the sump to the circulating pump and through the circulating pump to the distributor, the distributor itself, and particularly the evaporator plate or ice molding surfaces or fins designed in the ice-forming trays made a part of the evaporator plate and in close proximity or attached directly to the evaporator external surfaces.
When these deposits form, they inhibit water flow, increase corrosion of the metal surfaces, inhibit heat transfer efficiencies, and generally cause poor operation of the ice maker, which, in turn, can lead to poor ice formation and in some cases bad tasting or bad looking ice (white ice).
Cleaning/Sterilizing System
The cleaning/sterilizing system can minimally include control and monitoring capabilities permitting manual or automatic shutdown of the coolant/refrigerant system followed by emptying the water accumulated in the water/ice system by opening the drain valve 9 for a time sufficient to empty the water to the drain. After this time has passed, the solenoid drain valve 9 automatically closes, fresh water from supply 1 is added to the system, and water pump 4 begins circulation. Fresh water is circulated for a prescribed period of time, as programmed into the controller and the pump is turned off, the drain valve 9 is opened, and the cleaning water evacuated to the drain 10. The procedure is repeated at least 3 times, preferably from 4-6 times. If desired, a cleaning solution may be added manually to the first rinse water when machines of this invention are operating without the add-on cleaning/sterilizing system 59 of FIGS. 1, 4 and 5.
The preferred self-cleaning system which is contained in or can be connected to the automatic ice machine 30 described above comprises at least one cleaning/sterilizing solution reservoir, at least one injection device servicing the reservoir, interconnecting feed lines from the reservoirs to the suction side of this injection mechanism, optional check valves or solenoid valves installed between the injection mechanism and the water system, and an injection line connector into the circulation water lines, or alternatively directly into the water reservoir or sump of the water/ice system. The cleaning/sterilizing injection line then feeds either or both the cleaning solution and sterilizing solution into the water/ice circulating system liquid. This line operates to feed the cleaning solution, or can operate to feed the sterilizing solution, or may operate to feed both cleaning and sterilizing solutions, in any sequence, or simultaneously.
FIGS. 4 and 5 provide information regarding the cleaning solution/sterilizing solution storage vessels or containers, connecting lines, injection mechanism or devices, check valves, the cleaning/sterilizing injection lines, the electronic control panels, and the like.
In FIG. 4A, which is an inside view of the add-on box 59 of FIG. 1A, a vinyl tube 50 is supplied to reach nearly to the bottom of a storage bottle or vessel 51. This vessel 51 can contain cleaning solution or sterilizing solution 52 or both if appropriate. The invention may operate with a single bottle or storage vessel with cleaning solution, a single storage vessel with sterilizing solution, or with multiple storage vessels and injection mechanisms for both cleaning and sterilizing solutions. Preferably, as seen in FIG. 4B, which is a schematic representation of a front view of the add-on system of FIG. 4A, the system contains two vessels 51, separate connecting lines, and separate injection pumps for separately storing and delivering cleaning and sterilizing solutions. The plastic cap 53 to the bottle 51 is tightly screwed to the bottle top and the bottle top is vented to prevent vacuum from crushing the solution containers as cleaning or sterilizing solution is withdrawn therefrom. Alternatively, the cap 53 is loosely fitted permitting vacuum break-through air leakage.
The vinyl tube 50 is connected to the suction inlet of an injection mechanism, or in FIG. 4A, a dispensing pump or injection pump 54, which dispensing pump 54 can be any positive displacement pump, such as a gear pump, a syringe pump, a piston pump, an oscillation pump, a peristaltic pump or any kind of pump or positive delivery device capable of delivering a measured amount of cleaning or sterilizing solution. In FIG. 4A, the outlet 55 of said dispensing pump 54 is connected to another delivery tube 56, which delivery tube (or injection line) is either fed directly to the water sump or may optionally be teed into the water supply line, preferably at a location prior to the inlet or suction side of the circulation pump of the water/ice system. When the cleaning solution is fed directly into the water sump, this is done preferably above the level of water held therein so that an air gap prevents water from the ice machine being siphoned or drawn back into the cleaning/sterilizing solutions.
Although the injection mechanisms depicted in the drawings are positive displacement pumps, other mechanisms are possible and are to be included within the meaning of the term “injection mechanism.” For example, the storage vessels could be inverted, having a gravity flow to the water/ice system, and the cleaning/sanitizing flow controlled by a check valve, or possibly by the combination of a check valve and a venturi eductor located in the water/ice circulation lines.
The add-on cleaning/sanitizing system may be comfortably held within an apparatus case or container 59 which case 59 itself may have mounting slots 57, as in FIGS. 4A and 4B, for easy mounting internally or externally (see FIG. 1A) on the surfaces of the ice machine. In fact, wall surfaces external to the ice machine structures may be useful for mounting our cleaning/sterilizing system. (See FIG. 1B.) Similarly, the apparatus case may be mobile and brought to and connected with an ice machine equipped to accept the cleaning system contained therein.
Depicted also in FIG. 4A is a control board 58. In FIG. 5, the control board 58 is depicted in further detail. The control board 58 contains a relay 61, an LED light tube 62, a modular female connector 63, a cleaning frequency selector switch, 64, and a momentary pump switch or priming switch 65. Also depicted in FIG. 4A is an electric power cord 67 and an electric line 66 to the dispensing pump 54. Each of these devices may be manually operated or, when connected to the ice machine, may be monitored and operated by the microprocessor and controlling/monitoring system.
The methods and systems described below provide unique and novel solutions in preventing the ingress of organisms, as well as creating an environment within the ice making compartment that is not conducive to the formation (growth) of the organisms.
The present disclosure also provides many additional advantages, which shall become apparent as described below.